[EXT] Re: [PATCH 1/3] dma-buf: heaps: add Linaro secure dmabuf heap support

[Nicolas Dufresne]

Hi Folks,

Le mardi 16 août 2022 à 11:20 +0000, Olivier Masse a écrit :
> Hi Brian,
> 
> 
> On ven., 2022-08-12 at 17:39 +0100, Brian Starkey wrote:
> > Caution: EXT Ema
> > 

[...]

> > 
> > Interesting, that's not how the devices I've worked on operated.
> > 
> > Are you saying that you have to have a display controller driver
> > running in the TEE to display one of these buffers?
> 
> In fact the display controller is managing 3 plans : UI, PiP and
> video. The video plan is protected in secure as you can see on slide
> 11:
> https://static.linaro.org/connect/san19/presentations/san19-107.pdf



just wanted to highlight that all the WPE/GStreamer bit in this presentation is
based on NXP Vendor Media CODEC design, which rely on their own i.MX VPU API. I
don't see any effort to extend this to a wider audience. It is not explaining
how this can work with a mainline kernel with v4l2 stateful or stateless drivers
and generic GStreamer/FFMPEG/Chromium support.

I'm raising this, since I'm worried that no one cares of solving that high level
problem from a generic point of view. In that context, any additions to the
mainline Linux kernel can only be flawed and will only serves specific vendors
and not the larger audience.

Another aspect, is that this design might be bound to a specific (NXP ?)
security design. I've learn recently that newer HW is going to use multiple
level of MMU (like virtual machines do) to protect the memory rather then
marking pages. Will all this work for that too ?

regards,
Nicolas